PLT OF A PIPER PA31-350; DECLARED AN EMER AND RETURNED TO LAND DURING CLBOUT DUE TO CATASTROPHIC R ENG FAILURE WITH ACCOMPANYING ENG FIRE.

Narrative

ON THE MORNING OF MAY/THU/98; I DEPARTED FAIRBANKS INTL ON A VFR FLT PLAN ENRTE TO FORT YUKON. THE ACFT FLOWN WAS A PIPER NAVAJO PA31-350. PRIOR TO DEP; AN ENG RUN-UP WAS PERFORMED. NO ABNORMAL ENG INDICATIONS WERE NOTED. AFTER DEP WHILE CLBING THROUGH APPROX 4000 FT THE R ENG SPUTTERED JUST FOR A MOMENT. ABOUT 3 OR 4 SECONDS LATER THERE WAS A MUFFLED POP AND IMMEDIATE LOSS OF PWR ON THE R ENG. I IMMEDIATELY PERFORMED THE EMER PROCS FOR AN ENG FAILURE AND STARTED A TURN BACK TO THE ARPT. WHILE IN THE TURN I NOTED THE ENG OIL FILLER COVER ON THE COWLING HAD BEEN BLOWN OPEN AND THAT A PROFUSE AMOUNT OF OIL WAS STREAMING OUT OVER THE WHOLE COWLING. THROUGH THE LOUVERS ON THE COWLING; I COULD ALSO SEE A FIRE IN THE AREA OF THE TURBOCHARGER. THIS INCIDENT OCCURRED APPROX 15 MI N OF FAIRBANKS WHERE I INFORMED GND CTL OF MY SIT; THAT I WAS DECLARING AN EMER AND REQUESTING FIRE CREWS TO BE WAITING. ABOUT 30-45 SECONDS AFTER NOTING THE FIRE IT APPEARED TO HAVE EXTINGUISHED ITSELF. A NORMAL LNDG WITHOUT INCIDENT WAS PERFORMED ON RWY 19R. UPON EXITING THE RWY I ELECTED TO TAXI THE ACFT ON 1 ENG TO MY COMPANY'S RAMP AREA. THE FIRE CREWS WERE FOLLOWING CLOSELY BEHIND ESCORTING ME ALL THE WAY TO MY COMPANY. UPON INVESTIGATION OF THE ENG; IT WAS FOUND THAT THE #5 CYLINDER HAD SEPARATED ITSELF FROM THE ENG CASE. IN ADDITION; A LARGE AREA OF THE ENG CASE ITSELF (APPROX 8- 10 INCH DIAMETER) SEPARATED FROM THE ENG. IT WAS DISCOVERED THAT THE CYLINDER WHICH SEPARATED FROM THE ENG WAS AN ORIGINAL CYLINDER. THE ENG HAD APPROX 60-70 HRS TO GO BEFORE TIME BTWN OVERHAULS. THE ONLY THING I WOULD HAVE DONE DIFFERENTLY IN THIS EVENT WOULD HAVE BEEN TO SHUT THE ACFT DOWN IMMEDIATELY UPON EXITING THE RWY INSTEAD OF TAXIING TO MY COMPANY FOR FEAR OF A SECONDARY FIRE; IRREGARDLESS OF FIRE CREWS BEING READILY AVAILABLE.